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Image Source: https://www.calpaclab.com/water-hplc-spectro-grade-4-liter-bottles-case-4/ted-ws2211-001

When ordering HPLC/Spectro grade Water for HPLC from certain vendors(not all), it comes in an amber coloured bottle. From my understanding, H2O is not photosensitive, so why is there a need to sell/store/transport it in an amber glass?

While amber bottles offer protection, most HPLC systems have built-in safeguards like filters or closed loops that minimize light exposure and aid in purification. Also, in some rare cases, if the quality is not that great, the pigment in the amber bottles could leach and lead to unwanted contaminants. So, is the amber colour, in this case, just an aesthetic benefit or a marketing gimmick? Or does it still have some practical use that I missed out on!

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    $\begingroup$ Under the light, some living forms often find the way to survive and grow. Typically algae. $\endgroup$
    – Poutnik
    Commented Jun 18 at 4:29
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    $\begingroup$ Some LC people are against storing water in amber glass bottles because if something manages to grow inside, it will be harder to spot. There is an opinion that a fresh water from a MilliQ/Rephile system in a clear bottle is better. $\endgroup$
    – andselisk ♦
    Commented Jun 18 at 5:25
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    $\begingroup$ In one lab I worked in past, where deionized water was used for glass washing, they used a yellow foil wrapping the cylindrical vessel. It filtered blue light portion needed by algae to grow but still allowed visual inspection. $\endgroup$
    – Poutnik
    Commented Jun 18 at 9:21

1 Answer 1

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As explained in the comments, brown bottles for HPLC, or LC-MS grade water absorb useful wavelengths for algae growth (red and blue). This is where chlorophyll absorbs. This graph shows a quantitative UV-Vis blocking performance of amber glass: Source

spectrum

As a side note, the concept of pure water is perhaps a hypothetical construct and a marketing gimmick. Water from commercial deionizers is good enough for most HPLC work. A while ago, I saw a poster in a conference, which showed that it takes only 30 minutes in a laboratory for MilliQ or high-purity water to become "contaminated" with carbon dioxide, chloride, and ammonium ions. Chloride ion is everywhere in an ordinary laboratory environment and so is ammonia. The resistance of ultrapure water drop rapidly as it greedy absorber of everything at low concentrations. Similarly, glass will leach sodium ions slowly in HPLC grade water. There are more metals in HPLC grade water at parts per billion levels. The main thing is that HPLC grade water is free from UV absorbing impurities and the metals do not interfere in most cases, except LC-MS where sodium ion forms adducts with the analytes shifting the masses by 23 units or multiples thereof.

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